The present invention relates to a system and method for detecting hazardous materials inside articles and, more particularly, to a system and method for detecting hazardous materials inside mail.
All economies depend upon the physical shipment of materials for their functioning including the shipment of mail, merchandise, raw materials, and other goods.
In some circumstances, it is desirable to subject the goods to some type of inspection to determine the presence of hazardous or impermissible materials, including biological and chemical materials. In general, sophisticated sensing systems are known for the detection of hazardous biological and chemical materials. For example, such systems can include conventional laboratory facilities as well as mobile or semi-mobile units that can automatically or semi-automatically detect the presence of the undesired substance or substances. One such vehicle-mobile system is the Joint Biological Point Detection System (JBPDS) developed for the United States military and designed to detect the presence of a number of biological pathogens. Others include sensor or detectors for hazardous chemicals, explosives, illicit drugs, radioactive particles, and other hazardous materials. These sensors can be used single, or in combinations, to detect as many types of hazardous particles or vapors as required.
Currently when there is suspicious mail, it is all bulk irradiated, as was done during the recent anthrax problem in the U.S., thereby delaying some mail for months and damaging or destroying some of the mail due to problems caused by the irradiation. For example, some of this irradiated mail becomes brittle and pieces break off.
U.S. Published Application No. US 2002/0126008 published Sep. 12, 2002 and filed Oct. 31, 2001 discloses use of sensors at various locations within a typical mail processing system to sense the presence of a harmful agent. This system is completely open to the ambient atmosphere. (The present application is based upon a provisional patent application filed Oct. 26, 2001.)
U.S. Published Application No. US 2002/0124664 published Sep. 12, 2002 and filed Feb. 1, 2002 discloses use of a mail sampling system used in a room separate from the remainder of a post office facility and in which there is an air intake fan and all outgoing air is filtered before release. Most often openings are formed in the parcels and mail for the sampling. The sampling system is said to determine whether mail is contaminated with a chemical or biological agent. (The present application is based upon a provisional patent application filed Oct. 26, 2001.)
U.S. Pat. Nos. 5,942,699 and 6,324,927 disclose a manner of collective sampling of cargo items for contaminants such as chemical residues. The cargo items are placed into a special airtight chamber and physically agitated, such as by vibration, to release particulates and vapors from the items, and bursts of high pressure air is sent into the chamber. Heated air may also be used.
U.S. Pat. No. 3,915,339 discloses use of pressurized air into a container to loosen and cause free flow of material therein move.
U.S. Pat. No. 3,998,101 discloses a method and apparatus for sampling the atmosphere in non-hermetically-sealed containers by enclosing baggage in a chamber and varying the air pressure cyclically to mix a portion of the air in the baggage with the air in the chamber and a vapor detector is used to detect the presence of explosives or drugs in the baggage.
U.S. Pat. No. 4,580,440 discloses a method of detecting a contraband substance in freight cargo in which the container is agitated to disturb particulates therein and samples are taken of the air containing such particulates. The collected particulates are heated to drive off vapors indicative of the contraband substance and the vapors are analyzed in a mass analyzer.
U.S. Pat. No. 4,718,268 discloses a method and apparatus for detecting a contraband substance in freight cargo similar to that of U.S. Pat. No. 4,580,440 mentioned above.
U.S. Pat. No. 5,841,038 discloses a remote sampling device for possibly hazardous content of a container. A hollow needle punctures the container and is used to withdraw the contents or to introduce another substance. An inert gas can be introduced into the area where the needle punctures the container.
U.S. Pat. No. 5,859,362 discloses a trace vapor detection method and device of sampling a volume of air suspected of containing drug vapors, removing particulate matter and binding vapors of the drug for further analysis. The device has sampling, filtration and vacuum port components.
U.S. Pat. No. 6,295,860 for explosive detection system and sample collecting device in which luggage enters the device and leaves the device after inspection in which a vapor leaking from the luggage is sampled by a sampling probe, negative corona discharge is used to ionize the vapor, and a mass spectrometer is used to detect the ionized vapor to determine whether or not an explosive is present.
Patent Abstracts of Japan Pub. No. 02159554 A published Dec. 12, 1988, Application No. 63313358 discloses a monitoring method of a pathogen or allergen in which a biosensor is provided near a suction port for air conditioning provided for each room of wall surface which tends to gather mold.
WO 91/09307 published Jun. 27, 1991, for Explosive Detection Screening System detects vapor or particulate emissions from explosives and other controlled substances and reports their presence and may also report the concentration. There is a sampling chamber for collection of vapors or other controlled substances and a concentration and analyzing system, and a control and data processing system for the control of the overall system. There are a number of U.S. patents in this series, including the following: U.S. Pat. Nos. 4,987,767; 5,109,691; 5,345,809; 5,465,607; and 5,585,575.
The US Postal Service has no reliable manner of determining if anthrax, or other hazardous materials, are contaminating items of mail. It is desirable to do this before mail enters sorting and distribution centers. The present invention provides a system and method for detecting hazardous materials in or on mail.
The present invention is a system and method for detecting contaminants in and around objects, including mail pieces and parcels, and may include neutralizing the environment containing the contaminants or the contaminants themselves. The system of the present invention may include, but is not limited to, a housing such as a cabinet, a perforated container or surface, an air duct subsystem, a power subsystem, a sensor subsystem, an indicator subsystem, and a controller. Optionally, the system of the present invention can include a blower subsystem and a neutralization subsystem.
The housing creates an enclosure and forms an airflow barrier between the enclosure and the outside ambient air. The housing has a housing opening for inserting and removing the object(s). When there is a container, it forms a cavity for holding the object(s). The container has a shell with a plurality of perforations, or may be made of wire in which case there are already openings, and it is rotatably mounted within the housing. The container has at least one container opening for inserting and removing the object(s). When there is a surface with openings, the objects are supported by the surface. The power subsystem, operably connected to the container, rotates the container, or shakes or agitates or vibrates the surface.
The sensor subsystem tests an air stream for contaminants. The indicator subsystem is operably connected to the sensor subsystem and provides a signal when at least one contaminant is detected.
The air duct subsystem is capable of ducting the air stream to an appropriate place within the system. In one embodiment, the air duct subsystem can duct the air stream into a perforated pipe that is mounted within the container or adjacent to the perforated surface. The perforated pipe allows the air stream to enter in one case the cavity and in the other case perforations in the surface and the perforations allow the air stream to flow through and about the articles. The air duct subsystem can receive the air stream from the enclosure and/or adjacent the perforated surface and can duct it past the sensor subsystem, optionally forced by the blower subsystem.
Current devices that could detect and safeguard against biological agents can present further problems such as introducing additional contaminants into the air sample that may cause false alarms or shorten the life span of contaminant detection devices. Some current devices are deficient in that they allow the migration of deadly contaminants to the outside environment, or they require the use of costly high efficiency particle air filters (HEPA) filters to process air before release to the outside environment.
In one type of arrangement, the unit is self-contained and is a closed loop system in which the air is recirculated and not allowed to enter the ambient atmosphere. In such a system a HEPA filter is not needed.
The air duct subsystem is capable of ducting the air stream in a closed loop throughout the system. The air duct subsystem can duct the air stream into a perforated pipe that is mounted within the container. The perforated pipe allows the air stream to enter the cavity, and the perforation(s) in the cavity allows the air stream to enter the enclosure. The air duct subsystem can receive the air stream from the enclosure and can duct it past the sensor subsystem and back through the housing into the container, optionally forced by the blower subsystem.
In another type of arrangement, the air is filtered and then released to the atmosphere.
In another embodiment, there are air inlet and outlet openings in the container which permit air to enter and to leave.
The controller sequences operations among the sensor subsystem and the power subsystem so that particles that can be emitted while the object(s) are being tumbled within the cavity when the container is rotating. The particles can pass through the perforation(s) in the container from the cavity to the housing and then are entrained with the air stream into the air duct subsystem. The air stream and particles exit the housing and are ducted past the sensor subsystem which sends a signal to the indicator subsystem if contaminant(s) is detected in the particles.
Optionally, the blower subsystem can force the air stream through the air duct subsystem. If a blower subsystem is used to force the air stream, the controller can sequence activities among the blower subsystem, the sensor subsystem, and the power subsystem. Also optionally, when contaminant(s) is detected, a neutralization mechanism can inject a conventional contaminant neutralizer such as chlorine-calcium, formalin, or lye solutions into the air stream in the air duct subsystem. If a neutralization mechanism is used, the controller can sequence activities among the neutralization mechanism, the sensor subsystem, and the power subsystem, and optionally the blower subsystem.
The method of the present invention includes the steps of loading a perforated container or surface with at least one object, enclosing the perforated container or surface within a housing, and sealing the housing. In this method, the step of sealing forms an ambient air barrier which prevents air and particles emitted from the perforated container or surface into the housing from entering the ambient air outside the housing. The method of the present invention further includes the step of rotating the perforated container or vibrating the perforated surface. Rotation of the perforated container that contains objects can serve to release particles that are on and in the objects within the perforated container into an air stream that entrains emitted particles. It also includes, in another embodiment, the step of vibrating the perforated surface to release hazardous particles that are on and in the objects within the housing. The method further includes the step of sampling the air stream that enters the housing through the perforations in the container or surface. The method includes the steps of testing for at least one contaminant and providing an indicator if at least one contaminant is detected. The method can optionally include the steps of forcing air into the rotating perforated container, which in turn is forced through the perforations into the housing or forcing air in the vicinity of the perforated vibrating surface, and introducing a neutralizing agent into the air stream if the air stream contains at least one contaminant.
The container is not filled to capacity so as to allow room for the mail to xe2x80x9cwaterfallxe2x80x9d during rotation. The speed may be adjustable so that the mail can tumble and collide. If desired, this can be made variable using software based upon the load that is sensed by sensors which are a part of the system using such software.
In one type of system air flow is established within a container to sweep hazardous particles that are entrained in the interior air and dislodge particles from surfaces therein and sweep the particles into a sensor unit for analysis. A container may be provided with at least one wall surface, which, in one embodiment, is the floor surface, as an air distribution plenum with air-flow holes or openings therein to allow the establishment of an air flow path within the container.
During the time that the air flow pattern is established, a hazardous-materials detection sensor or sensor system is located at or otherwise introduced into the air flow pattern, preferably at or downstream of the air exit port, for a sufficient period of time to sample the flow for a plurality of undesired or hazardous materials.
The distribution plate or surface defines an air distribution plenum therebeneath and includes a plurality of holes distributed across its surface. The air flow pattern can be established by an air-moving fan located within the container or by an auxiliary piece of equipment that connects to the container through an air inlet port and air outlet port to establish a desired air recirculation flow for some period of time. Once the flow has been established, a sensor or sensors are located within the exhaust flow for some period of time sufficient to effect the detection of any undesired or hazardous materials.
The present invention advantageously provides a system and method for quickly and efficiently detecting hazardous materials inside housings while the shipped materials are contained and prior to the unloading of the housing and possible dissemination/distribution of any hazardous materials.
Other features and advantages will be apparent from the following detailed description of preferred embodiments taken in conjunction with the accompanying drawings.